Sorting is a function that must be performed in many droplet-based microfluidic biological applications. For example, when performing a cellular screen, cells having the desirable trait must be extracted from the full population of cells by droplet sorting. In the example of sequencing DNA, drops containing undesirable products, or lacking the target DNA, must be removed by sorting, so that they are not processed in the steps that follow. Droplet sorting can be achieved using a variety of methods. For example, using single layer membrane valves or by pressuring bifurcating channel geometry, droplets can be sorted into different channels. Alternatively, by using dielectrophoretic forces or surface acoustic waves, droplets can be sorted at much higher speeds.